I'm no MBA, but my understanding is that there is a big difference between being a minority investor/share owner, and owning the kind of stock from the sale proposed by the Cubs.
Minority owners do get to share in the profits, even if they don't get to vote on business decisions and management direction and stuff like that.
Ownership of shares to be sold by the Cubs probably gets you an uber-cool membership card, a secret decoder ring, and a stock certificate suitable for framing. In other words, fleecing the blue sheep for easy cash.